1. Field of the Invention
This invention relates to an RF excited laser which incorporates a ceramic bore and more particularly to an RF excited laser which has an internally folded resonator.
2. Description of the Prior Art
U.S. Pat. No. 4,464,760, frame entitled Elongated Chamber for Use in Combination with a Transversely Excited Gas Laser, issued to Leroy V. Sutter, Jr. on Aug. 7, 1984, teaches an laser bore and electrode structure which includes a ceramic bore. process
U.S. Pat. No. 4,723,256, entitled Optical Resonator for Laser Oscillating Apparatus, issued to Ethan D. Hoag on Feb. 2, 1988, teaches an optical resonator for a laser oscillating apparatus which has an arrangement of folding mirrors facing one another across the lasing gas medium that radiates the laser beam. The arrangement includes a pair of reflecting surface which are approximately orthogonal to one another and effectively face the lasing gas medium an a whole. Also, the laser beam which is incident from the lasing gas medium is caused to be reflected successively from both reflecting surfaces to be emitted in the direction of the lasing gas medium.
U.S. Pat. No. 4,499,582, entitled Laser System, issued to Henrich Karning, Franz Prein and Karl-Heinz Vierling on Feb. 12, 1985, teaches a laser system with a folded beam path which is formed by a plurality of mirrors. Each mirror reflects light in a closed loop from one mirror to another mirror. Electrodes are disposed on opposite sides of the path between the mirrors and form channels through which the folded beam path extends.
U.S. Pat. No. 4,446,559, entitled Laser with Annular Resonator, issued to Karlheinz von Bieren on May 1, 1984, teaches a laser resonator in which the extent of diffraction is controlled in order to provide the desired oscillation sustaining feedback.
U.S. Pat. No. 4,352,188, entitled RF Pumped Waveguide Laser with Inductive Loading for Enhancing Discharge Uniformity, issued to Glen A. Griffith on Sept. 28, 1982, 048918056 teaches a discharge-excited waveguide gas laser which utilizes a transverse RF excitation voltage at a frequency of at least about 30 MHz applied between elongated electrodes on opposite sides of the laser discharge chamber and which a plurality of shunt inductances coupled between the electrodes externally along the length of the chamber. These inductances provide a negative admittance which compensates for the variation in the phase angle of the transmission line reflection coefficient along the length of the laser discharge chamber. The variation in the magnitude of the standing wave voltage is reduced accordingly thereby improving the uniformity of the laser-exciting discharge.
U.S. Pat. No. 4,169,251, teaches Waveguide Gas Laser with High Frequency Transverse Discharge Excitation, issued to Katherine D. Laakman on Sept. 25, 1979, teaches waveguide lasers which are excited by a transverse discharge at RF frequencies generally in the vhf-uhf range, i.e., from about 30 MHz to about 3 GHz. These excitation frequencies are sufficiently high to ensure negligible interaction of discharge electrons with the discharge-establishing electrodes, thereby achieving superior discharge properties which result in a laser of improved performance and reduced size and complexity.
U.S. Pat. No. 4,103,255, entitled High Power, Compact Waveguide Gas Laser, issued Howard R. Schlossberg on July 25, 1978, teaches a high power, compact waveguide gas laser housing located within a resonant cavity. The housing has a longitudinal chamber situated therein. The chamber is divided into a plurality of waveguides by a plurality of infrared transmitting partitions. During operation of the laser, the leakage of laser radiation between adjacent waveguides through the partitions causes coupling of the phases of the waveguide modes thereby producing a laser output of high power.
U.S. Pat. No. 4,468,776, entitled Reinjection Laser Oscillator and Method, issued to Edward J. McLellan on Aug. 28, 1984, teaches a uv preionized carbon dioxide oscillator with integral four-pass amplifier which is capable of providing 1 to 5 GW laser pulses with pulse widths from 0.1 to 0.5 nanoseconds, full width at half maximum (FWHM). The apparatus is operated at any pressure from 1 atm to 10 atm without the necessity of complex high voltage electronics. The reinjection technique employed gives rise to a compact, efficient system that is particularly immune to alignment instabilities with a minimal amount of hardware and complexity.
U.S. Pat. No. 4,679,201, entitled Folded CO.sub.2 Laser, issued to Hans Klingel on July 7, 1987, teaches a folded longitudinal carbon dioxide laser with an output of at least several hundred watts which has a geometrical longitudinal axis, a rectilinear tube device of dielectric material containing carbon dioxide.
U.S. Pat. No. 4,703,491, entitled Optical System for Folded Cavity Laser, issued to Gnian C. Lim on Oct. 27, 1987, teaches an optical system for a folded cavity laser which has a partially transmitting output mirror and a fully reflective folding mirror on one side of an active laser medium, and another folding mirror on the other side of the active laser medium disposed so that a resonating laser beam inside the resonator cavity may make multiple passes to obtain a long effective cavity length. Mechanisms are provided for adjusting at least one of the folding mirrors so that the laser beam resonates within the cavity. Mechanisms are also provided for adjusting the output mirror so that misalignments of the folding mirrors are compensated.
U.S. Pat. No. 4,740,986, entitled Laser Resonator, issued to Robin A. Reeder on Apr. 26, 1988, teaches a radiation folding waveguide which includes a reflector. The reflector transmits incident radiation. The reflector has a longitudinal axis along its longest dimension and a bottom edge colinear with the longitudinal axis.
U.S. Pat. No. 4,723,256, entitled Optical Resonator and for Laser Oscillating Apparatus, issued to Ethan D. Hoag on Feb. 2, 1988, teaches an optical resonator for a laser oscillating apparatus which includes a plurality of mirrors which are disposed within a hollow cylindrical housing which define a lasing region therein including a large front folding mirror at one end of the lasing region, a relatively larger rear folding mirror disposed at the opposite end of the lasing region, a relatively small totally reflective concave primary mirror disposed adjacent the front folding mirror and a relatively small semi-transmissive front folding mirror and a relatively small transmissive output mirror is disposed adjacent to both the front and the primary mirror.